We now offer this for our product, and I know a lot of other sellers are doing the same. We used to only have a Prime (Fulfilled by Amazon) offer, but this crisis caused us to adapt as customers were getting 1-month delivery estimates.
We enabled "Fulfilled by Merchant" offers on our account, and I sent some inventory to my apartment (and ordered lots of shipping boxes). Within a couple days, the self-fulfilled option got the "buy box" on Amazon, so now most people viewing our listing will see a delivery estimate of about one week. It doesn't have the "Prime" badge, but we get a decent number of orders through this, enough to survive.
We send out all orders with First Class Mail, and I pack them up around 3PM each business day in order to get them to the post office by the 5PM cutoff. It appears most customers are receiving orders between 2 and 5 days after ordering (including the opposite coast). This is even faster than the time estimate customers see on Amazon, and way faster than Prime.
Disclaimer: your mileage may vary.